Method of and means for adjusting rotary spark gaps of wireless apparatus



April 14, 1925.

J. L. JENKS, JR

METHOD OF AND MEANS FOR ADJUSTING'ROTARY SPARK GAPS OF WIRELESS APPARATUS Filed Feb. 11, 1922 FIG. 1.

FIG. '7

FIG, 3.

Qwuzntoc Jmll Jan/1'6, Jr.

Patented Apr. 14, 1925.

UNITED STATES JAMES L. J'ENKS, JR. (3F MEDEURD, JLASSACI'IUSETTS.

METHOD or AND eans i on anansrrite nornnr sranx ears or WIRELESS nrraan'rns.

Application filed February 11, 1922. Serial No. 535,814.

To all whom it may concern:

Be it known thatLJArrns JENKs, Jr., a citizen of the United States of America, residing at Mcdford, in the county of Mich dlesex and State of hilassachusetts, have invented certain new and useful Improvements in Methods of and Means for Adjusting Rotary Spark Gaps of l Vireless Apparatus, of which the following is a specification.

This invention relates to certain new and useful lIIlPIOYGmGIltS in methods of and means for adjusting rotary spark gaps of wireless apparatus, and the invention has more particular reference to the provision of improvedmeans for obtaining the correct tone for transmission in synchronous gaps employed in radio-telegraphy,

One of the most efficient spark gaps used radio-telegraphy is the so-called synchro= no us gap. One form of synchronous gap very frequently met is that driven by a synchronousinotorv In thistype of syn- "chrOnousjgapthe correcttone for transmission' can onl be obtained when the stationary electrodes of thegap are in the correct position relative to therotating elec trodes. Thisadjustment mustbe very close, i. e.,'within one or two degrees on the circnmference ,ofthe discharge disk. In many gaps now being used the only method for obtainingthecorrecttone adjustment is to stop the synchronousgap and to changethe position ofthe discharge disk with-respect to; the motor shaft, again starting the motor for another trial. In other words, it is impossible to adjust for tone or synchronism wh le the gap is rotating.

" jsincefadjustment for synchronism must he made frequently, due to changing power ,condition'on the line .orin the transmitting transformer, some method of v adjustment while the gap is rotating would be very useful, l his';cond ition is fulfilled by the present invention which preferably consists ffof an adjustable reactance in series with the sta onary Wi in O th ynchron s Hi tor, thejjaction of whichis to cause the rotor, and hence the shaft to which the discharge diSlCis-attached, to 'lag -beind its normal position, the amount of lag depending upon the amountofreactance cut in.

"Broadly stated, therefore, the invention consists inadjnstinga synchronous gap by igurc 1 is a diagrammatic view partly in plan and partly in perspective sho ving a portion of a wireless transmission apparatus equipped with one form of tone adjusting mechanism in accordance with thepresent invention, 1 j i Figure'Q is a diagrammatic view illustrating the lagging effect on the synchronous motor, a

Figures 3 to 6 are developed diagrammatic, views showing points on the cycle where the spark of a synchronous ga jumps orwhere it is broken,

Figure 7 is a view somewhat similar to -1 with parts removed showing a ino ditied form of the invention,"and

Figure 8 shows a diagrammatic plan view of an adjustab be employed in lieu of the adjustable"reactance illustrated in 1.

Referring more in detail to the several views, and particularly to Fig. 1, "the numeral 5 designates the feed wires from denoted by the numeral 9 is placed in series with the stationary windings 7 clearly shown in Fig. 1, this reactance being controlled by a single throw switch member 10 or the like whereby the desired "amount of reactance may be thrown into circuit at will.

The rotor 6 is carried by a shaft 11 and this shaft also carries the disk 12 of the producing a lagging effect on the rotor of spark g p whi has u ua plureli y ofw radial electrodes 13 adapted to cooperate in the usual manner with stationary elec trodes employed at the points 14 as is usual, the stationary electrodes being in the oscillatory circuit 15 which includes an inductance 16, wires 17, a condenser 18 connected across said wires, and a high voltage transformer having a secondary 19 and a primary 20, the primary 20 being connected by means of wire 21 to the proper alternating current supply line.

The synchronous motor has the usual starting winding 22 which is connected directly across the line on the line side of the reactance 9 so that the adjustable reactance will have no effect upon said windings It will also be noted that this starting winding is automatically out out when the motor has come up to speed by means of a centrifugal switch diagrammatically illustrated at 23, and the starting winding is placed on the line side of the rcactance, in order that.

the starting torque of the motor will not be weakened materially by the aforesaid reactance.

The reactance 9 embodies a plurality of contacts 24 connected by suitable wires at different points on the coil of the'reactance and arranged in an arcuate manner so as to selectively cooperate with'the adjacent end of the pivoted member 10, the arrange- 'ment shown being such that downward swinging movement of the member 10 will out in more reactance and upward swinging thereof will cut out more of the same as found necessary to obtain the proper tone adjustment.

Referrin to Fig. 2, the rotor 6 and the stator pole are shown associated with dot and dash lines 25 and 26, which respectively indicate theposition of the rotor with respect to the stator at a given point on the sine-curve of the alternating current supply without any reaetance in the circuit, and the position of the rotor with respect to the stator at the same point on the sine curve as above, but with a reactance in series with the stator windings of the synchronous motor, showing how the rotor lags behind its normal position.

In Figs. 3 to 6 the rotary discharge disk 7 of the gap is indicated at 12 with the usual electrodes 13 cooperating with stationary electrodes at the points indicated. at 14. The sine curve 27 is denoted in Figs. 3 and f5 with points 28 where the spark jumps and at 29 in Flgs. at and6 where there is no discharge, the jumping of the spark being shown as occurring at the peak of the cuiwe V at each side of the line 30.

By the above means, a change of position or lag of 10 or more on the circumference of the discharge disk is easily possible, and

it is thus very easy to make all adjustments.

of tone while the gap is in rotation and to make the adjustments very accurately and even at a remote distance if desired.

IIIQORDQCUOD with the ad ustable react ance, several types are available. a closed core reactance with a tapped winding being probably the simplest to construct. As shown in F 7, the windings of the stator itself might be made variable by snnpl' connecting the stationary winding 7' at one side by means of a wire 8' to one of the line wires 5 and extending leads 3]. from different points of the winding 7 to a series of contacts 32 cooperating with a single throw switch arm 33 which is connected to the other line wire 5' by means of a wire 8'. Also, a differently wound stator would probably prove more eiiicient with the external reaetance control, i. e.. a stator with greater torque to counteract the loss of power incidental to the use of external reactance.

An adjustable air gap would give a finer degree of adjustment, but would have less range. Such an air gap is shown in Fig. 8 and includes a core of reactance 3% adapted to be connected by wire 35 to the alternatingcurrent line and by wire 36 to the stator, a yoke or equivalent member 37 being associated with the core34 and provided with means 38 for'adjusting its position with respect to the core whereby the air gap between the member 37 and the core 34 is variable.

It is of course understood that the adjustable reactance and the variable air gap are commonly used for numerous purposes in electrical practice, but the specific application of the same in the radio-telegraphy art as set forth herein is believed to be new and to produce beneficial and new results.

From the foregoing description it is believed that the construction and operation f the device will be readily understood as well as its advantages appreciated by those skilled in the art, and it is noted that when the device is in operation the reactance may be varied so as tochange the position of the rotor with respect to the phase of the line. The current lagging due to the added reactance makes the rotor lag behind normal, and this naturally gives, a close and accurate adjustment of the synchronous tone ofthe gap and has the following advantages over adjustable stationary electrodes.

The clearance of the stationary electrode can be closely adjusted to the rotor, all tone adjustments being accomplished by the variable reactance, thus eliminating the danger of disturbing clearance adjustment when rotatingthe electrodes during operation.

In many enclosed synchronous gaps, adjustment for tone cannot be made during operation, but by the adjustable reactance method shown herein, very close tone adjustment can be. obtained during actual operation.

The adjustment of tone can be remotely controlled by the adjustable reactance, eliminating all danger of shock to the operator and permitting adjustment of set Without leaving operating table.

It Will be seen that the electrical principle involved in this invention will be found in either form shown in Figs. 1 and 7 or in Fig. 8, the particular means for obtaining the result being the only difference.

Minor changes may be made in the invention Withoutdeparting from the spirit and scope thereof as claimed.

What is claimed as new is '1. That method of adjusting a rotary synchronous spark gap which includes a rotary spark and is directly driven by a synchronous motor Which consists in controlling the phase of thecurrent supplied to the motor and thereby regulating the discharge according to the spark gap.

2. In a radio apparatus, the combination with spark gaps including a rotary discharge disk, a synchronous motor driving the discharge disk and having rotary and stator 'Winds, and a common alternating current supply for said gap and motor; 01 means for controlling the phase of the current supply to the motor and thereby producing lag in the motor with-consequent lag in the spark gap.

8. In a radio apparatus, the combination with spark gaps including a rotary discharge disk, a synchronous motor driving the discharge disk and having rotary and statoravinds, and a common alternating current supply for said gap and motor; of means for controlling the phase of the current supply to the motorv and thereby pro ducing lag in the motor with consequent lag in the spark gap, said'means including a variable reactance in series With the stator windings oi the motor and means for manually adjusting said variable reactance.

In testimony whereof I affix my si nature.

JAMES L. ranks, JR. 

